CATALYTIC ASYMMETRIC EPOXIDATION AND AZIRIDINATION MEDIATED BY SULFURYLIDES - EVOLUTION OF A PROJECT

A novel, catalytic and asymmetric process fbr carbonyl epoxidation and imine aziridination has been developed. The processes utilise diazo c ompounds and the reactions are mediated by catalytic quantities of tra nsition metals (rhodium acetate or copper acetylacetonate) and sulfide s. In this catalytic cycle, the diazo compound is decomposed by the me tal to give metal carbenoid which reacts with the sulfide to give a su lfur ylide. This in turn reacts with the aldehyde to give an epoxide a nd returns the sulfide back into the catalytic cycle. Substitution of the aldehyde for an imine furnishes aziridines in high yield. Both epo xidation and aziridination can be rendered asymmetric by the use of ch iral sulfides in the catalytic process. This account describes how the se processes evolved.